From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Thierry Reding <thierry.reding@avionic-design.de>
Cc: linux-tegra@vger.kernel.org,
Grant Likely <grant.likely@secretlab.ca>,
Rob Herring <rob.herring@calxeda.com>,
Stephen Warren <swarren@wwwdotorg.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Andrew Murray <andrew.murray@arm.com>,
Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
Arnd Bergmann <arnd@arndb.de>,
Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
devicetree-discuss@lists.ozlabs.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH 05/14] lib: Add I/O map cache implementation
Date: Wed, 9 Jan 2013 21:28:47 +0000 [thread overview]
Message-ID: <20130109212847.GT3931@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1357764194-12677-6-git-send-email-thierry.reding@avionic-design.de>
On Wed, Jan 09, 2013 at 09:43:05PM +0100, Thierry Reding wrote:
> The I/O map cache is used to map large regions of physical memory in
> smaller chunks to avoid running out of vmalloc()/ioremap() space.
>
> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
We already have a means where we record the mappings which ioremap()
creates. If you look at /proc/vmallocinfo, you'll notice lines such
as:
0xf7b72000-0xf7b74000 8192 e1000_probe+0x291/0xa68 [e1000e] phys=fc025000 ioremap
which gives you the virtual address range, physical address and type
of the mapping. Why do we need a duplicated data structure?
Moreover, you seem to suggest that you want to break up a large
ioremap() mapping into several smaller mappings. Why? The idea
behind ioremap() is that this relationship holds true:
ptr = ioremap(cookie + n, size);
For any 'n' in the range 0 .. size, the location shall be accessible
via ptr + n when using the IO space accessors. If you're going to
break up a mapping into several smaller ones, this no longer holds
true.
If the problem is that you're ioremapping huge address ranges because
you're passing larger-than-required resources to devices, then that's
part of the problem too.
next prev parent reply other threads:[~2013-01-09 21:30 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-09 20:43 [PATCH 00/14] Rewrite Tegra PCIe driver Thierry Reding
2013-01-09 20:43 ` [PATCH 01/14] of/pci: Provide support for parsing PCI DT ranges property Thierry Reding
2013-01-11 0:06 ` Stephen Warren
2013-01-11 4:02 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 02/14] of/pci: Add of_pci_get_devfn() function Thierry Reding
2013-01-11 0:09 ` Stephen Warren
2013-01-11 4:06 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 03/14] of/pci: Add of_pci_get_bus() function Thierry Reding
2013-01-09 20:43 ` [PATCH 04/14] of/pci: Add of_pci_parse_bus_range() function Thierry Reding
2013-01-09 20:43 ` [PATCH 05/14] lib: Add I/O map cache implementation Thierry Reding
2013-01-09 21:19 ` Arnd Bergmann
2013-01-09 21:54 ` Thierry Reding
2013-01-09 22:10 ` Arnd Bergmann
2013-01-09 23:12 ` Stephen Warren
2013-01-09 23:17 ` Jason Gunthorpe
2013-01-10 7:19 ` Thierry Reding
2013-01-10 9:17 ` Arnd Bergmann
2013-01-10 10:25 ` Thierry Reding
2013-01-10 18:20 ` Jason Gunthorpe
2013-01-10 18:55 ` Thierry Reding
2013-01-10 19:03 ` Thierry Reding
2013-01-10 19:24 ` Jason Gunthorpe
2013-01-10 20:20 ` Thierry Reding
2013-01-10 21:06 ` Jason Gunthorpe
2013-01-16 10:18 ` Thierry Reding
2013-01-16 11:25 ` Russell King - ARM Linux
2013-01-16 11:52 ` Thierry Reding
2013-01-10 18:26 ` Arnd Bergmann
2013-01-10 18:57 ` Thierry Reding
2013-01-10 7:10 ` Thierry Reding
2013-01-09 21:28 ` Russell King - ARM Linux [this message]
2013-01-09 21:57 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 06/14] ARM: pci: Keep pci_common_init() around after init Thierry Reding
2013-02-05 20:41 ` Thierry Reding
2013-02-06 16:30 ` Russell King - ARM Linux
2013-02-06 19:35 ` Thierry Reding
2013-02-06 8:36 ` Thomas Petazzoni
2013-02-06 16:38 ` Linus Walleij
2013-02-07 0:54 ` Arnd Bergmann
2013-02-06 17:07 ` Linus Walleij
2013-02-07 1:20 ` Arnd Bergmann
2013-01-09 20:43 ` [PATCH 07/14] ARM: pci: Allow passing per-controller private data Thierry Reding
2013-01-09 20:43 ` [PATCH 08/14] ARM: tegra: Move tegra_pcie_xclk_clamp() to PMC Thierry Reding
2013-01-09 20:43 ` [PATCH 09/14] ARM: tegra: Move pmc.h to include/mach Thierry Reding
2013-01-11 0:15 ` Stephen Warren
2013-01-11 4:08 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 10/14] PCI: tegra: Move PCIe driver to drivers/pci/host Thierry Reding
2013-01-09 21:22 ` Arnd Bergmann
2013-01-09 21:58 ` Thierry Reding
2013-01-09 22:03 ` Arnd Bergmann
2013-01-10 23:54 ` Stephen Warren
2013-01-11 3:40 ` Thierry Reding
2013-01-11 15:36 ` Arnd Bergmann
2013-01-11 15:45 ` Thierry Reding
2013-01-12 12:36 ` Thierry Reding
2013-01-12 21:12 ` Arnd Bergmann
2013-01-13 9:58 ` Thierry Reding
2013-01-14 9:57 ` Andrew Murray
2013-01-15 12:08 ` Thierry Reding
2013-01-15 12:44 ` Arnd Bergmann
2013-01-15 15:40 ` Andrew Murray
2013-01-15 21:14 ` Thierry Reding
2013-01-16 14:00 ` Arnd Bergmann
2013-01-16 16:17 ` Andrew Murray
2013-01-16 18:31 ` Thierry Reding
2013-01-17 15:42 ` Andrew Murray
2013-01-17 16:05 ` Thierry Reding
2013-01-17 16:22 ` Andrew Murray
2013-01-17 20:30 ` Thierry Reding
2013-01-18 9:18 ` Andrew Murray
2013-01-22 19:29 ` Jason Gunthorpe
2013-01-29 13:31 ` Andrew Murray
2013-01-11 0:48 ` Stephen Warren
2013-01-11 3:52 ` Thierry Reding
2013-01-11 20:34 ` Stephen Warren
2013-01-18 9:56 ` Andrew Murray
2013-01-18 10:09 ` Thierry Reding
2013-02-13 23:11 ` Thomas Petazzoni
2013-01-09 20:43 ` [PATCH 11/14] ARM: tegra: tamonten: Add PCIe support Thierry Reding
2013-01-09 21:23 ` Arnd Bergmann
2013-01-10 20:21 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 12/14] ARM: tegra: tec: " Thierry Reding
2013-01-11 0:22 ` Stephen Warren
2013-01-11 4:34 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 13/14] ARM: tegra: harmony: Initialize PCIe from DT Thierry Reding
2013-01-10 23:58 ` Stephen Warren
2013-01-09 20:43 ` [PATCH 14/14] ARM: tegra: trimslice: " Thierry Reding
2013-01-10 23:56 ` Stephen Warren
2013-01-11 18:48 ` Thierry Reding
2013-01-09 21:25 ` [PATCH 00/14] Rewrite Tegra PCIe driver Thomas Petazzoni
2013-01-10 6:55 ` Thierry Reding
2013-01-10 8:34 ` Thomas Petazzoni
2013-01-28 18:15 ` Bjorn Helgaas
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